VRSPV Soft-Start Strategy and AICS Technique for Boost Converters to Improve the Start-Up Performance

Soft-start strategy is very important for boost converters to guarantee the stability of the output voltage. However, previous methods may cause large initial inrush current and long output voltage settling time. In this paper, a variable ramp-slope with predefined voltage (VRSPV) soft-start strategy is proposed. As a result, one branch of the initial inrush current is successfully eliminated and the output settling time of the boost converter is shortened by using the variable slope soft-start voltage. Also, an adaptive inrush current suppressing (AICS) technique is designed. The series resistance of the output capacitor is adaptively regulated by AICS technique to further suppress the initial inrush current. Finally, the VRSPV strategy and AICS technique are combined and implemented in a voltage-mode boost converter. The measurement results show that the peak initial inrush current and settling time are decreased by 60% and 40%, respectively. The output voltage of the boost converter increases smoothly during the soft-start period and finally achieves stability. The proposed method of combining VRSPV strategy and AICS technique is very suitable to be integrated on a chip to save the printed circuit board area and cost.